The present invention relates to a stereo picture recognition device and a method of displaying the stereo picture for recognizing, without sensing flicker, the stereo picture which is displayed by a time-sharing system.
As is seen in FIG. 8, there is provided a stereo picture recognition device (stereo picture display system) using a pair of liquid crystal shutter glasses, according to an earlier technology. In FIG. 8, there are shown a cathode ray tube 1 (hereinafter referred to as “CRT 1”) used as a stereo display device, and a pair of liquid crystal shutter glasses 2. A viewer facing the CRT 1 and wearing the liquid crystal shutter glasses 2 allows a right liquid crystal shutter 2R to be disposed in front of a right eye 100R of the viewer, and a left liquid crystal shutter 2L to be disposed in front of a left eye 100L of the viewer.
As is seen in FIG. 9(a), there is shown a period at which a right video signal 11R for the right eye 100R and a left video signal 11L for the left eye 100L are supplied. On a display surface of the CRT 1, the right video signal 11R and the left video signal 11L are alternately displayed at a vertical scanning period. Synchronously with this, as is seen in FIG. 9(b) and FIG. 9(c), switching transmission-and-shutoff operations of the right liquid crystal shutter 2R and the left liquid crystal shutter 2L leads images, respectively, to the right eye 100R and the left eye 100L. The thus led right image and left image are different from each other.
Taking into account right-and-left parallax for the thus led respective right image and left image allows the viewer to sense (feel) stereoscopic about the picture.
As is seen in FIG. 10, the liquid crystal shutter glasses 2 are constituted of a liquid crystal sealing body 15 (glass plate), a first linear polarization filter 16, a second linear polarization filter 17, and a light attenuation filter 18. The first linear polarization filter 16 and the second linear polarization filter 17 are so disposed adjacent to the liquid crystal sealing body 15 as to put therebetween the liquid crystal sealing body 15. The light attenuation filter 18 is disposed adjacent to the first linear polarization filter 16 facing the CRT 1.
As is seen in FIG. 10, in the stereo picture display system according to the earlier technology, it is not only in an area covered by a viewing angle A that the left eye 100L (right eye 100R as well) shuts off external light at the period in FIG. 9(b) {for right eye 100R, FIG. 9(c)}, but also in an area covered by a viewing angle B and a viewing angle C. Basically, the viewing angle A is for viewing a screen (or a picture plane) of the CRT 1, while the viewing angle B and the viewing angle C are for viewing an area other than the screen of the CRT 1.
This causes the viewer to sense flicker in a surrounding landscape, especially when the external light is bright, to thereby make the viewer tired. Moreover, when frequency of light transmitting through the liquid crystal shutter glasses 2 is close to frequency of an illumination (such as a fluorescent lamp and the like), the flicker is encouraged.
As is seen in FIG. 10, surround brightness is attenuated to half or below due to the first linear polarization filter 16 of the liquid crystal shutter glasses 2. Moreover, the time-sharing system as is seen FIG. 9(a), FIG. 9(b) and FIG. 9(c) reduces viewing time by half for viewing outside. Thereby, transmission is reduced to ¼ or below, to thereby provide a poor surround visibility.
For reducing the flicker, the light attenuation filter 18 (ND filter) is added to the stereo picture recognition device in FIG. 10. This further reduces the transmission, to thereby cause a further poorer surround visibility. Such poor surround visibility is even dangerous.